The best part of playing a girl possessed by demons in that you don’t have to worry about hair and makeup. “I have no dignity anymore after this movie,” says Olivia Cooke, star of “The Quiet Ones” (opening Friday). She’s in a hospital gown, wrenching, screaming and partially on fire for part of the film.

The best part of playing a girl possessed by demons in that you don’t have to worry about hair and makeup.

“I have no dignity anymore after this movie,” says Olivia Cooke, star of “The Quiet Ones” (opening Friday). She’s in a hospital gown, wrenching, screaming and partially on fire for part of the film. You wouldn’t exactly call it a glam role.

“It’s really lovely not to feel like you have to be playing the pretty girl,” says the London newcomer, who is making her mark in the world of scare fare. Cooke has a role on A&E’s “Bates Motel” as the one Norman wants to make his main squeeze. Soon, she will star in “Ouija,” about a board game that runs amok.

In “The Quiet Ones,” she’s Jane Harper, a young woman who has grown up in asylums because an evil spirit possesses her. An Oxford professor (Jared Harris) springs her and keeps her captive in a creepy mansion because he’s determined to prove that she has in fact conjured all this up in her mind.

“Jane is so feral. She’s 18, dealing with a demon inside of her and discovering her sexuality. You could say it’s a confusing time for her,” says the actress, a big-screen beauty in real life.

“I played Jane like she was a truly disturbed person,” she says. “She’s tormented. She has been shifted from asylum to asylum and finally meets Jared’s character. He’s her last chance before she wants to end it all.”

Being confined to a small locked room for most the movie wasn’t unnerving for Cooke.

“It was oddly comfortable,” she says. “I was honestly confined there for numerous hours of the day with bright sunshine outside. I’d peel back the newspapers covering my windows to see the fun and run around barefoot in my room.”

As her possessed scenes and the thrashing they involved, she says, “It was a physically demanding movie. I’m burning up and tearing people to pieces. But I said I would do anything for this movie, including hold my breath for five minutes. I just said yes. And it was the most fun ever.

“After the scary scenes, we would stop and sing. I’d sing ‘Moulin Rouge’ and Sam Claflin would sing ‘West Side Story.’ It was our way to break the tension.”

On “Bates Motel,” she’s Emma, who has captured Normie’s eye.

“Emma just lost her virginity to someone who is not Norman,” she says. “She just wants her normal relationship back on track with Norman, meaning they should be friends. You can tell from his demeanor that he’s not too happy about being friends.”

Signing for the series was a career dream come true.

“I got ‘Bates Motel’ when I was 18. ‘Quiet Ones’ is my third job. I never trained or went to drama school,” marvels the Manchester, England native. “I did do some work in an amateur theater group, but I was never formally trained.”

At 14, she got her first agent. “They didn’t think I was cool enough to act, so they put me up for commercials,” she says. “I did some really cringy commercials and then a casting agent fought for me to get a BBC miniseries.”

She did “Blackout” and then “The Secret of Crickley Hall.” “Now I love acting. I’m lucky to have this career.”

Next, she will star in more scary stuff, including “The Signal” due out this summer. “Three girls take a trip across the country to track down a hacker,” she says. “The unknown happens and we end up in an underground bunker.”

And how scary is “Ouija,” due out next year? “I’m the heroine in that one and I get to save people,” she promises. “Basically, it’s about me trying to find out how my friend died around this Ouija board. We ask questions about how she died and it just all goes wrong.”